Spiking Neural Networks (SNNs) are bio-inspired networks that process information conveyed as temporal spikes rather than numeric values. An example of a sensor providing such data is the event camera. It only produces an event when a pixel reports a significant brightness change. Similarly, the spiking neuron of an SNN only produces a spike whenever a significant number of spikes occur within a short period of time. Due to their spike-based computational model, SNNs can process output from event-based, asynchronous sensors without any pre-processing at extremely lower power unlike standard artificial neural networks. This is possible due to specialized neuromorphic hardware that implements the highly-parallelizable concept of SNNs in silicon. Yet, SNNs have not enjoyed the same rise of popularity as artificial neural networks. This not only stems from the fact that their input format is rather unconventional but also due to the challenges in training spiking networks. Despite their temporal nature and recent algorithmic advances, they have been mostly evaluated on classification problems. We propose, for the first time, a temporal regression problem of numerical values given events from an event camera.

We specifically investigate the prediction of the 3-DOF angular velocity of a rotating event camera with an SNN. The difficulty of this problem arises from the prediction of angular velocities continuously in time directly from irregular, asynchronous event-based input. Directly utilizing the output of event cameras without any pre-processing ensures that we inherit all the benefits that they provide over conventional cameras. That is high-temporal resolution, high-dynamic range and no motion blur. To assess the performance of SNNs on this task, we introduce a synthetic event camera dataset generated from real-world panoramic images and show that we can successfully train an SNN to perform angular velocity regression.

Reference:
M. Gehrig, S. Shrestha, D. Mouritzen, D. Scaramuzza.
Event-Based Angular Velocity Regression with Spiking Networks
IEEE International Conference on Robotics and Automation (ICRA), Paris, 2020
PDF: http://rpg.ifi.uzh.ch/docs/ICRA20_Geh...
Code: https://github.com/uzh-rpg/snn_angula...

Our research page on event based vision: http://rpg.ifi.uzh.ch/research_dvs.html

For an event camera simulator: http://rpg.ifi.uzh.ch/esim/index.html

For a survey paper on event cameras, see here:
http://rpg.ifi.uzh.ch/docs/EventVisio...

Other resources on event cameras (publications, software, drivers, where to buy, etc.):
https://github.com/uzh-rpg/event-base...

Affiliation:
M. Gehrig, S. Shrestha, D. Mouritzen and D. Scaramuzza are with the Robotics and Perception Group, Dept. of Informatics, University of Zurich, and Dept. of Neuroinformatics, University of Zurich and ETH Zurich, Switzerland http://rpg.ifi.uzh.ch/